Apparatus for modifying an electrical signal

Abstract: The present invention provides an apparatus for altering an electrical signal between a first device and a second device. The apparatus includes a support structure or interconnection member having at least two surfaces with a plurality of contacts on each surface. The contacts are arranged in a predesignated pattern to mate with the conductors of each of the devices. In a typical application, the apparatus will be used to connect a microprocessor powered by approximately 3.3V to a printed circuit board of a system using a power supply of approximately 5.0V.

Description: This invention relates to an apparatus for modifying an electrical signal passing between first and second devices, and particularly to an apparatus for regulating a voltage signal between two electrical components, such as a microprocessor and a printed circuit board to which the microprocessor is mounted. The printed circuit board could, for example, be situated in a device such as a computer. In the electronics industry, and particularly in the computer industry, electrical signals are often transmitted between devices or components at a multiplicity of contact points. One example is a microprocessor having a large number of contact pins connected to corresponding contacts on, for instance, a printed circuit board within a computer. Typically, the microprocessor will have a pin grid array appropriately configured for mating engagement with corresponding contacts arranged in some type of socket or receptacle. Generally, standard voltages are used to power various electrical components, such as microprocessors. For example, computers generally use a supply voltage of approximately 5.0V to power various digital hardware devices. In certain applications, this can be problematic because heat is generated when current is supplied at 5.0V. As electrical devices are continually downsized, such heat generation becomes a greater problem. In certain applications, microprocessors must be packaged in ceramic pin grid array packages which can withstand the heat. Cheaper plastic packages may melt or be otherwise damaged by excess heat. Ceramic packaging is more expensive to manufacture than plastic packaging, leading to increased cost of the finished product. Certain electrical components are presently available which can be powered by 3.3V, which creates substantially less heat than higher (e.g., 5.0V) supply voltages. For example, certain microprocessor chips, such as the Am 486™ 3.3V manufactured by Advanced Micro Devices, can be powered by 3.3V and are available in plastic packages called plastic quad flat packages. The Am 486™ 3.3V microprocessor chip is specially designed to allow the core microprocessor to operate at 3.3V while providing compatible external signals of approximately 5.0V. This allows the chip to function on about one-half the power of a conventional 5.0V chip. Such chips or devices are also beneficial since the plastic quad flat package is a much narrower package than the conventional ceramic package. This is particularly advantageous when space is limited. One problem, of course, is that many devices are powered by the standard 5.0V power supply and 3.3V components, such as 3.3V microprocessors, cannot be used unless the power supply is converted from approximately 5.0V to approximately 3.3V. However, creating electrical signal conversion circuitry is generally costly and space consuming. Converting the electrical signal from one level to another is particularly difficult in tight spaces where there are multiple contacts, as with a microprocessor or other digital components. US-A-4,652,065 describes a laminated semiconductor termination socket which has a pattern of sockets on one side for receiving the pins of a semiconductor chip package, and a pattern of pins on the opposite side for plugging in to a printed circuit board. According to the present invention there is provided apparatus for coupling a first device with a second device to effect electrical communication between a plurality of first connection means on the first device and a plurality of second connection means on the second device, the apparatus comprising: a generally flat interconnection member having opposed generally parallel surfaces, a first of the surfaces having a first plurality of electrical connection elements adapted to engage the said first connection means of the first device and the opposed surface having a second plurality of electrical connection elements adapted to engage the said second connection means of the second device, characterised in that the interconnection member further comprises an altering circuit operatively connected between selected connection elements of the first plurality of electrical connection elements and selected connection elements of the second plurality of electrical connection elements for altering the electrical signals communicated by the interconnection member between the first device and the second device. Preferably, the first connection elements comprise a plurality of conductive pads or receptacles on the first surface and the second connection elements comprise a plurality of conductive pins on the opposed surface. Preferably, the altering circuit includes a voltage regulator which regulates or changes a voltage signal communicated between selected first connectors of the first connection means and selected second connectors of the second connection means. In a specific application of the apparatus, the first device is a microprocessor chip contained in a plastic quad flat package, and the second device is a printed circuit board. The altering circuit, preferably including a voltage regulator and a pair of capacitors, is operatively connected between the first plurality of contacts and the second plurality of contacts to reduce the voltage supplied at the printed circuit board to a desired lower voltage for powering the microprocessor. In the accompanying drawings, by way of example only: Fig. 1 is an exploded view of the apparatus embodying the present invention disposed between a first device and a second device; Fig. 2 is a bottom view of the apparatus; and Fig. 3 is an electrical schematic diagram of a circuit for altering an electrical signal between a first device and a second device. In Fig. 1, an apparatus 10 is disposed between a first device 12 and a second device 14. Apparatus 10 can be made in a variety of shapes and configurations and can be used to conduct electrical signals between a variety of different types of devices, 12, 14. However, in the following description, apparatus 10 will be described in a configuration for use between a first device 12, such as a microprocessor 16 housed in a plastic quad flat package 18, and a circuit board 20 of the type used in a computer or any of a variety of electrical devices. It should also be noted that apparatus 10 could be used to alter a variety of electrical communications or electrical signal characteristics, but for exemplary purposes in this description, apparatus 10 will be described as altering a voltage supplied from second device 14 to first device 12. Apparatus 10 includes an interconnection member 22 which can take a variety of forms or shapes depending on the specific application and the specific devices 12, 14 that are used. Interconnection member 22 includes a plurality of first contacts 24 and a plurality of second contacts 26. Preferably, first contacts 24 are supported in a first surface 28 and second contacts 26 are supported in a second surface 30. First surface 28 and second surface 30 may also be formed in a variety of configurations and orientations, but in the exemplary embodiment being described, they are generally parallel to one another and closely spaced. Both first contacts 24 and second contacts 26 are arranged in predetermined configurations for mating engagement with first device 12 and second device 14, respectively. Apparatus 10 also includes an electric signal altering device 32, preferably including electrical circuitry for altering the electrical signal between second device 14 and first device 12. Altering device 32 is interconnected between at least a portion of first contacts 24 and at least a portion of second contacts 26 so that the electrical signal being communicated between second device 14 and first device 12 is appropriately altered. In the illustrated embodiment, altering device 32 includes a voltage regulator 34, such as the MC33269 low dropout positive voltage regulator manufactured by Motorola, Inc., of Schaumburg, Illinois. In addition, altering circuit 32 preferably includes a first capacitor 36 operatively connected intermediate voltage regulator 34 and the selected portion of first contacts 24. Altering circuit 32 also includes a second capacitor 38 operatively connected intermediate voltage regulator 34 and the corresponding selected portion of second contacts 26. First capacitor 36 and second capacitor 38 must be selected according to the particular application. However, when used with the Motorola MC33269 voltage regulator to reduce voltage from approximately 5.0V to approximately 3.3V, first capacitor 36 is preferably a ten microfarad capacitor, such as the capacitor having part number T 411B106M025AS manufactured by Kemet Electronics Corporation of Greenville, South Carolina, and second capacitor 38 is a 0.1 microfarad capacitor, such as the capacitor having part number C 0805A 104K5XAC manufactured by Kemet Electronics Corporation. In the most preferred embodiment, interconnection member 22 includes a thin support member 39, preferably rectangular and having an edge 40 extending about its perimeter and separating first surface 28 from second surface 30. Support member 39 may be made from a variety of insulative type materials, including plastic. Although Figure 1 illustrates support member 39 as a generally solid structure, member 39 could also include apertures, a hollow interior, or its first and second surfaces 28, 30 could be held in a spaced relation by a variety of internal support structures. Additionally, first contacts 24 are preferably supported in first surface 28 and can take a variety of configurations. For example, the contacts could be sockets, pins, or pads depending on the type of connectors used on first device 12. In fact, first device 12 could even be hard-wired to contacts 24, although it is preferably surface mounted to pads 42 supported in or arrayed on first surface 28 of support member 39. Similarly, the plurality of second contacts 26 can take a variety of configurations including sockets, pins, pads, or direct hardwiring depending on the type of second device 14. In the most preferred embodiment, second contacts 26 are pins appropriately arranged in an array for plugging into second device 14, e.g. a socket on a printed circuit board. Pins 44 may be attached directly to support member 39 or may be purchased as a prearranged pin grid array package 46 having a plastic base 48 for rigidly holding pins 44 in the appropriate predetermined pattern for interconnection with second device 14. Pin grid array package 46 is then mounted to support member 39 by any of a variety of methods, such as surface mounting. Pins 44 of package 46 may be surface mounted to corresponding pads on support member 39. As mentioned above, first device 12 may be of a variety of types, but for purposes of this detailed description, the microprocessor 16 encapsulated in plastic quad flat package 18 will be described. One great advantage of this invention is that it can be used with microprocessor chips such as the Am 486™ 3.3V chip packaged in a plastic quad flat package to present a space-conserving package. In this instance, first device 12 includes the generally flat package 18 having a pair of generally parallel surfaces 50 separated by an edge 52. A plurality of conductive connectors 54 are operatively connected (not shown) to microprocessor chip 16 and extend from edge 52 in an arrangement corresponding to the array of first contacts 24. Thus, connectors 54 may be surface mounted to pads 42 when first device 12 is operatively engaged with apparatus 10. The mounting methods will vary depending on the device, but surface mounting is preferred using attachment mechanisms such as solder or epoxy. Similarly, second device 14 may be of a variety of types and configurations but will typically include some type of circuit board 20 having a mounting area or socket 56 configured for receiving apparatus 10. Mounting area 56 will include a plurality of second conductive connectors 58 configured and arranged to receive the plurality of second contacts 26. In the illustrated embodiment, second conductive connectors 58 are sockets arranged to receive pins 44. Optionally, apparatus 10 may include a heat sink 60. Heat sink 60 may include a variety of large traces, bars, or fins arranged within or adjacent interconnection member 22 and extending into proximity or into contact with electric signal altering device 32. Heat sink 60 assists in dispersing any heat produced by altering device 32 as it modifies or alters an electric signal communicated between second device 14 and first device 12. Fig. 2 is a bottom view of the preferred embodiment of the present invention. In Fig. 2, components of altering device 32, such as voltage regulator 34 and capacitors 36 and 38 are mounted to interconnection member 22 in a generally central location to accommodate the predetermined array of pins 44. Preferably interconnection member 22 includes a recess 62 for at least partially receiving voltage regulator 34 and capacitors 36 and 38. Recess 62 allows for a thinner apparatus 10 so that first device 12 and second device 14 may be connected in a space efficient manner. Voltage regulator 34 and capacitors 36, 38 are preferably surface mounted to selected first contacts 24 and selected second contacts 26 in a manner more clearly illustrated by the circuit diagram in Fig. 3. Figure 3 is an electrical schematic diagram of a circuit for altering an electrical signal communicated between a first device and a second device. In Fig. 3, an electrical signal, such as a 5.0V signal is supplied at selected connectors 66 of second connectors 58. The electrical signal at connectors 66 is then supplied to selected second contacts 68 of second contacts 26 and to altering circuit 64 which modifies or alters the signal. In this particular exemplary case, altering circuit 64 changes the original electrical signal supplied at selected connectors 66 from approximately 5.0V to an altered electrical signal. The altered electrical signal has a value of approximately 3.3V. The altered electrical signal is then supplied to selected first contacts 70 of first contacts 24 and corresponding selected connectors 72 of the first connectors 54 located on first device 12. It should be noted that in the typical situation the main electrical supply signal of 5.0V is not supplied at every connector 58 of second device 14 to be received by every connector 54 of first device 12. For instance, there may be a variety of signals including 5.0V signals, ground signals, and logic signals. Only selected conductors 66 and 72 carry the 5.0V supply signal. The remaining second connectors 58 and first connectors 54 may be connected in appropriate corresponding relationship to facilitate operation of the microprocessor 16, but electrical signals communicated therebetween are not altered by altering circuit 64. As illustrated in Fig. 3, altering circuit 64 includes voltage regulator 34 connected intermediate selected contacts 68 and 70. First capacitor 36 is operably connected intermediate an output terminal 74 of voltage regulator 34 and first selected contacts 70. Second capacitor 38 is connected intermediate second selected contact 68 and an input terminal 76 of voltage regulator 34. As illustrated, both first capacitor 36 and second capacitor 38 are also connected to a ground terminal 78 of voltage regulator 34. Thus, in operation the original electrical signal supplied at approximately 5.0V to selected conductors 66 is reduced by altering circuit 64 to approximately a 3.3V electric signal at selected conductors 72 of first device 12. This allows a lower cost microprocessor chip packaged in a plastic quad flat package (PQFP) and powered by a 3.3V supply, to be used with conventional 5.0V systems. Such 3.3V microprocessors use less energy and generate less heat than 5.0V microprocessors, allowing them to be packaged in less expensive plastic. It will be understood that the foregoing description is of a preferred exemplary embodiment of this invention, and that the invention is not limited to the specific form shown. For example, the interconnection member may be made in a variety of configurations and manufactured from a variety of materials. The contacts may also be made in a variety of configurations, the circuitry can be adapted to alter electrical signals in ways other than reduction in voltage, and the apparatus may be used to interconnect a variety of devices which function using dissimilar electrical signals. These and other modifications may be made in the design and arrangement of the elements without departing from the scope of the invention as expressed in the appended claims.

Claims: Apparatus for coupling a first device (12) with a second device (14) to effect electrical communication between a plurality of first connection means (54, 24) on the first device and a plurality of second connection means (58, 26) on the second device, the apparatus comprising: a generally flat interconnection member (10) having opposed generally parallel surfaces (28, 30), a first (28) of the surfaces having a first plurality of electrical connection elements (24) adapted to engage the said first connection means (54, 24) of the first device and the opposed surface (30) having a second plurality of electrical connection elements (26) adapted to engage the said second connection means (58, 26) of the second device, characterised in that the interconnection member (10) further comprises an altering circuit (32) operatively connected between selected connection elements of the first plurality of electrical connection elements (24) and selected connection elements of the second plurality of electrical connection elements (26) for altering the electrical signals communicated by the interconnection member (10) between the first device (12) and the second device (14). Apparatus according to claim 1 wherein the altering circuit (32) includes a voltage regulator (34). Apparatus according to claim 1 or claim 2 wherein the first plurality of electrical connection elements (24) are conductive pads. Apparatus according to claim 3 wherein the second plurality of electrical connection elements (26) are conductive pins (44). Apparatus according to claim 3 wherein the second plurality of electrical connection elements (26) comprise conductive pads connected to a plurality of corresponding pins. Apparatus according to claim 5 wherein the plurality of corresponding pins are held in a pin assembly which is surface mounted to the said pads. Apparatus according to claim 1 or claim 2 wherein the first plurality of electrical connection elements (24) are conductive receptacles. Apparatus according to claim 2 wherein the altering circuit (32) includes a first capacitor (36) operably connected between the voltage regulator (34) and selected connection elements of the said first plurality of connection elements (24). Apparatus according to claim 8 wherein the altering circuit (32) includes a second capacitor (38) operably connected between the voltage regulator (34) and selected connection elements of the said second plurality of connection elements (26). Apparatus according to claim 9 wherein the voltage regulator (34) converts selected 5.0V signals to approximately 3.3V. Apparatus according to claim 2 wherein the voltage regulator (34) is disposed at least partially in a recess of the interconnection member (10). Apparatus according to any one of the preceding claims further comprising a heat sink configured to dissipate heat generated by the altering circuit (32). An electrical assembly wherein apparatus according to any one of the preceding claims is used to effect the said coupling between the first device (12) and the second device (14). An assembly according to claim 13 wherein the first device (12) includes a plastic quad flat package (18) having a microprocessor (16) configured for operative connection with the first plurality of connection elements (24). An assembly according to claim 13 or claim 14 wherein the second device (14) includes a printed circuit board (20) configured for operative connection with the second plurality of connection elements (26). An assembly according to claim 15 wherein the first device (12) is surface mounted to the said first plurality of connection elements (24). An assembly according to claim 15 wherein the first device (12) and/or the second device (14) are hard wired to the said first plurality of connection elements (24) and the said second plurality of connection elements (26), respectively.

Inventors: DULEY RAYMOND S, DULEY, RAYMOND S.
Applicants: ADVANCED MICRO DEVICES INC, ADVANCED MICRO DEVICES INC.
Application year: 1994
Main classification: H01R31
IPC codes: H05K1, H01R12, H01R29, H05K7, H05K3, H01L23, H01R27, H01R31